Nanotube molecular probes: DNA hybridization using single walled carbon nanotubes as biomarkers

Single walled carbon nanotubes (SWNTs) hold particular advantage as optical nano-bio markers because they exhibit strong Raman signals. Such signals do not blink or photobleach under prolonged excitation. Here, new single-stranded DNA conjugated SWNT probes were developed to locate a particular sequence of DNA within a complex genome. Chromosomal DNAs of human fibroblast and <i>Escherichia coli (E.coli</i>) were used as a target and a control, respectively. Southern blotting, which uses photostable Raman signals of nanotubes instead of fluorescent dyes, demonstrated excellent sensitivity and specificity of the probes. The results showed SWNTs' possibility of being generic nano-bio markers for precise detection of specific kinds of genes.